Hello,
I am working on a project to develop a compact EEG AFE for a battery operated µC system. Three AFEs are under consideration for this project, ADS1299, ADS1298 and ADS1198. Afterwards it'd be integrated with a micro controller via SPI. Preliminary thoughts are as follows.
ADS1299
Pros:
- No pre amp required.
cons:
- The maximum available supply voltage for this project is only 3V, so I cant use ADS1299 (requires 4.75 V min) though it have a very low i/p referred noise and higher programmable gain.
- High current and power consumption. Not advisable for battery operated applications. ?
ADS1298
Pros:
- 24 bit ADC. At vref=2.4V, can resolve upto .14µV.
- From Table 2 of datasheet, Input-Referred Noise is only 2.9µVpp at PGA G=12 and SR=500
Cons:
- Need pre amp(eg INA333) for each channel for a better SNR?
- i/p referred noise =3-4 µV
ADS1198
Pros:
- Low power consumption
Cons:
- i/p referred noise = 6 at G=12 and SR=500
- Pre amps needed. Takes up more space.
It would be great if anyone worked with these systems will comment on this observation. Do I have to use pre amps for ADS1298 systems ?
Thanks in advance.
Alex.